The primary function of hydrochloric acid treatment (HAT) is to create the maximum number of high-conductivity channels in the near-wellbore zone of the reservoir to restore its permeability and enhance hydraulic connectivity between the undisturbed part of the formation and the well. The objective of this study is to physically model HAT on core samples from the Orenburg oil and gas condensate field and to research the impact of such treatment on the structure of the pore space of rocks related to complex-type reservoirs. The complexity of the rock's pore space and the low permeability of the formations are distinguishing features of the study object. For this reason, HAT is a widely applied method for production intensification, necessitating the verification of acid injection rates, where the success criterion is the formation of high-conductivity filtration channels (wormholes) in the near-wellbore zone. These channels significantly expand the drainage area of wells, thereby bringing additional reservoir sections into development. The study examined the characteristics of filtration channel development resulting from acid treatment. Their structure was characterized and analyzed using X-ray computed tomography. The complex study confirmed the accuracy of the selected injection rate and provided practical recommendations for enhancing the efficiency of HAT.
The article discusses the issues of justifying the data volume for a petrophysical description of an object based on the results of traditional laboratory measurements, as well as X-ray tomography data processing. A new approach to the calculation of porosity and permeability properties of reservoirs with the data of the X-ray tomography method by forming an array of virtual cubes is considered. The issues of required number of allocated cubes for fluid dynamics modeling are discussed. The criteria for the number of laboratory measurements and virtual cubes derived from a digital model for obtaining statistically reliable petrophysical connections are shown. Paper concludes that it is necessary to correctly compare the calculated and laboratory petrophysical connections.
